On 15/09/2026 16:48, Leo Yan wrote:
The pause and stop callbacks duplicate the sequence that updates a sink buffer and finishes the current AUX output transaction. Move the common sequence into etm_event_update_buffer() for a single implementation.
The helper first verifies that perf handle is active. It updates the buffer when PERF_EF_UPDATE is requested and otherwise ends the transaction without data. The pause callback can then start a new perf handle for resuming trace.
Assisted-by: Codex:gpt-6 Signed-off-by: Leo Yan leo.yan@arm.com
drivers/hwtracing/coresight/coresight-etm-perf.c | 89 ++++++++++-------------- 1 file changed, 36 insertions(+), 53 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c index a45f69f39f175f3044322b25fe5413fb97154496..13d865ca86f1161b2e21174f096473c4829afc8c 100644 --- a/drivers/hwtracing/coresight/coresight-etm-perf.c +++ b/drivers/hwtracing/coresight/coresight-etm-perf.c @@ -637,6 +637,38 @@ static void etm_event_start(struct perf_event *event, int flags) return; } +static void etm_event_update_buffer(struct perf_output_handle *handle,
struct etm_event_data *event_data,struct coresight_device *sink,int mode)+{
- unsigned long size;
- /*
* Make sure the handle is still valid, as the sink may close it from* the IRQ handler. E.g., the sink driver may fail to restart the* handle during interrupt handling due to insufficient buffer space.* The sink driver must serialize update_buffer() with IRQ handling,* so this should return either a valid handle with a valid size* (which may be 0), or no handle at all.*/- if (!perf_get_aux(handle))
return;- if (!sink_ops(sink)->update_buffer)
goto out;- if (mode & PERF_EF_UPDATE) {
size = sink_ops(sink)->update_buffer(sink, handle,event_data->snk_config);perf_aux_output_end(handle, size);return;- }
+out:
- perf_aux_output_end(handle, 0);
+}
- static void etm_event_pause(struct coresight_path *path, struct perf_event *event, struct etm_ctxt *ctxt)
@@ -644,7 +676,6 @@ static void etm_event_pause(struct coresight_path *path, struct perf_output_handle *handle = &ctxt->handle; struct coresight_device *source, *sink; struct etm_event_data *event_data;
- unsigned long size;
if (!path) return; @@ -669,27 +700,16 @@ static void etm_event_pause(struct coresight_path *path, if (WARN_ON_ONCE(handle->event != event)) return;
- if (!sink_ops(sink)->update_buffer)
return;- event_data = READ_ONCE(ctxt->event_data);
- size = sink_ops(sink)->update_buffer(sink, handle,
event_data->snk_config);- if (READ_ONCE(handle->event)) {
if (!size)return;
- etm_event_update_buffer(handle, event_data, sink, PERF_EF_UPDATE);
perf_aux_output_end(handle, size);perf_aux_output_begin(handle, event);- } else {
WARN_ON_ONCE(size);- }
- /* Prepare the handle for resuming trace */
- perf_aux_output_begin(handle, event); }
static void etm_event_stop(struct perf_event *event, int mode) { int cpu = smp_processor_id();
- unsigned long size; struct coresight_device *source, *sink; struct etm_ctxt *ctxt = this_cpu_ptr(&etm_ctxt); struct perf_output_handle *handle = &ctxt->handle;
@@ -742,45 +762,8 @@ static void etm_event_stop(struct perf_event *event, int mode) /* tell the core */ event->hw.state = PERF_HES_STOPPED;
- /*
* If the handle is not bound to an event anymore* (e.g, the sink driver was unable to restart the* handle due to lack of buffer space), we don't* have to do anything here.*/- if (!handle->event)
goto out;- if (mode & PERF_EF_UPDATE) {
if (WARN_ON_ONCE(handle->event != event))goto out;/* update trace information */if (!sink_ops(sink)->update_buffer)goto out;
- etm_event_update_buffer(handle, event_data, sink, mode);
size = sink_ops(sink)->update_buffer(sink, handle,event_data->snk_config);/** Make sure the handle is still valid as the* sink could have closed it from an IRQ.* The sink driver must handle the race with* update_buffer() and IRQ. Thus either we* should get a valid handle and valid size* (which may be 0).** But we should never get a non-zero size with* an invalid handle.*/if (READ_ONCE(handle->event))perf_aux_output_end(handle, size);elseWARN_ON(size);- } else {
perf_aux_output_end(handle, 0);- }
-out: /* Disabling the path make its elements available to other sessions */ coresight_disable_path(path); }
Reviewed-by: James Clark james.clark@linaro.org